I recall reading an article in National Review (during the WFB era when I subscribed) and it discussed how beginning in the 1960s, even university degrees began to be dumbed down to that extent as to increase numbers at state run universities and thus get more public funding, etc. That’s why nowadays in California and elsewhere, one can study rap music as opposed to the genuine classics (literature, art, music, etc) as you’ve got many people in such places who would likely not be able to pass grade eight exams in language and math proficiency from two generations back or so.
Therefore, it is of course an easy thing to ban To Kill A Mockingbird or The Merchant of Venice and numerous other titles when you have the dumbing down taking place at the top.
I find most commercial rap music to be worthless, but I have heard some more interesting music played on the local university radio station, with rap style vocals but with jazz accompaniment, including good percussion parts. Better lyrics than commercial rap too.